A variety of products such as surfactants, functional fluids, glycol ethers, polyols, and the like, are commercially prepared by the condensation reaction of epoxides with organic compounds having at least one active hydrogen, generally, in the presence of an alkaline or acidic catalyst. The types and properties of the alkoxylation products depend on, among other things, the active hydrogen compound, the epoxide, and the mole ratio of epoxide to organic compound employed, as well as the catalyst. As a result of the alkoxylation, a mixture of condensation product species are obtained having a range of molecular weights.
In many applications of alkoxylated products, certain of the alkoxylation species provide much greater activity than others. Consequently, alkoxylation processes are desired that are selective to the production of those alkoxylation species. Further, for many of these uses, mixtures of alkoxylation products falling within a narrow range of molecular distribution of reacted epoxide are believed to be superior to alkoxylation products in which a single alkoxylation specie predominates. For example, in a surfactant composition the range of materials on which the surfactant will be required to operate will normally vary. A range of alkoxylation species, even though narrow, will enhance the performance of the surfactant to the variety of materials which it may encounter. Further, mixtures of closely related alkoxylation species can provide a mixture having other improved properties such as in respect to cloud point, freezing point, pour point and viscosity as compared to a single specie. There, however, is a balance, and if the distribution of species becomes too broad, not only are less desirable alkoxylation species diluting the mixture, but also the more hydrophilic or lipophilic components than those in the sought range can be detrimental to the sought properties.
Moreover, a wide range of alkoxylation species can restrict the flexibility in ultimate product formulation using the alkoxylation reaction product. For example, in making oil-in-water emulsion products it is often desired to prepare a concentrated composition that minimizes the weight percent of water. This concentrate may then be diluted with water at the time of use, thereby saving the expense of shipping and storing water. The ability to form a desirable concentrate is generally dependent, in part, on having a narrow distribution of alkoxylation species since its heavier moieties are present, a greater portion of water is usually required otherwise gelling (evidencing product instability) may occur.
The recognition that certain distributions of moles of epoxide to moles of organic compound in alkoxylation products can be important has long been recognized. For example, British Patent Specification No. 1,399,966 discloses the use of ethoxylates having a hydrophilic-lipophilic balance (HLB) of from about 10 to about 13.5 for use in a laundry detergent. In order to provide this HLB, the moles of ethylene oxide reacted per mole of fatty alcohol is described as being critical. In Bristish Patent Specification No. 1,462,133, the sought cleaning composition employed alkylene oxide cosurfactants sufficient to provide even a narrower HLB, i.e., from about 10 to about 12.5. In British Specification No. 1,462,134, a detergent composition is disclosed with uses ethoxylates having an HLB of from about 9.5 to 11.5, with the preferred ethoxylates having an HLB of 10.0 to 11.1.
Thus, with the increased understanding of the properties to be provided by an alkoxylation product, greater demands are placed on tailoring the manufacture of the alkoxylation product to enhance the sought properties. Accordingly, efforts have been expended to provide alkoxylated products in which the distribution of reacted epoxide units per mole of organic compound is limited to a range in which the sought properties are enhanced.